ES2746538T3 - Creating a digital restoration design - Google Patents

Abstract

A procedure for creating a digital restoration design (544, 644) using a computer to fabricate a dental restoration (433) for one or more of a patient's teeth, where the dental restoration is an upper restoration ( 433) for lifting the occlusal table (328) from the patient's teeth, wherein the procedure comprises: - obtaining a 3D digital representation (40, 540) of the patient's unprepared teeth (220, 327, 427); - obtaining a set of one or more digital tooth anatomies (539, 639) expressing the desired target shape of the patient's teeth; - arranging the digital anatomies of the teeth (539, 639) expressing the desired target shape of the patient's teeth and the 3D digital representation of the patient's unprepared teeth (220, 327, 427) according to a relative arrangement in the that the digital anatomies of the teeth (539, 639) expressing the desired target shape of the patient's teeth lift the patient's bite; and - creating a digital restoration design (544, 644) comprising a restoration margin line (546, 746) where the restoration margin line is obtained, at least partially, from an intersection (542) of the 3D digital representation (40, 540) of the patient's unprepared teeth (220, 327, 427) and digital tooth anatomies (539, 639) expressing the desired target shape of the patient's teeth.

Description

DESCRIPTION

Creating a digital restoration design

Technical field

This invention generally relates to digital restoration designs for the fabrication of dental restorations. More particularly, the invention relates to digital restoration designs created with minimal user interaction by establishing a restoration margin line for dental restoration.

Background

A patient may, for various reasons, wish to have an increased tooth size or a change in the shape and / or color of the teeth. This may be the case when the length of the teeth has been reduced due to, eg. ex. to the grinding of the teeth in the dream (Bruxism of the dream), or when the patient wishes to improve the aesthetic appearance of his teeth.

When a patient has worn teeth to the point of disrupting the patient's occlusion, the result may be that the patient begins to experience problems with their temporomandibular joint (TMJ). These problems can be solved by raising the bite so that the correct height of your occlusal table is recovered and, therefore, a correct movement of the TMJ. The bite can be lifted using a set of upper teeth arranged on the occlusal surface or incisal edge of the patient's teeth to replace the defective occlusal table of the patient's worn teeth. The phrase "lifting the occlusal surface / incisal edge of a tooth" refers to the situation where the occlusal surface / incisal edge of the tooth is moved further away from the cervical / apical part of the tooth. That is, when the patient's bite is lifted, the distance between the mandibular and maxillary bones of the occluded jaw increases.

The upper restoration preferably has a plurality of teeth that cover at least the occlusal table of the worn teeth, but the upper restoration does not necessarily cover the entire labial / buccal and lingual surface of the patient's teeth.

The restoration of the upper teeth does not necessarily require that the patient's teeth be prepared to allow the upper restoration to settle on the teeth. Especially for a superior temporary restoration, it may be advantageous to avoid extensive preparation of the patient's teeth until the bite has been lifted, i.e. until the patient has become accustomed to the corrected bite movement.

In prior art CAD software for designing dental restorations, the user must manually set the restoration margin line. The restore margin line can be set using, e.g. ex. a computer mouse to mark relevant points on a 3D digital representation of the patient's teeth displayed on, eg. ex. a computer screen.

The digital design of dental restorations, such as crowns or dental bridges, is often based on a 3D digital representation of the patient's teeth obtained after the teeth have been prepared to accept the dental restoration. Preparation often occurs when the dentist grinds the material of the tooth to make a dental stump, such as the so-called preparation, on which the dental restoration can sit. A restoration margin line is established, e.g. ex. from the tooth preparation line to the prepared tooth in 3D digital rendering. The operator then creates the digital restoration design from the restoration margin line, e.g. ex. modifying a tooth in the library so that it has the restoration margin line set.

International publication W02013079437 describes a procedure for generating a dental preparation guide configured to validate the preparation of at least one tooth for a dental restoration. The procedure includes: a: obtaining a 3D digital representation of a previously prepared set of teeth; b: virtually removing said at least one tooth from the 3D digital representation of the previously prepared set of teeth, so that a 3D digital representation of a remaining set of teeth is formed; c: provide an objective virtual dental restoration that expresses an objective form of the dental restoration; d: create a virtual validation surface for the dental preparation guide based on the target virtual dental restoration, where the validation surface is such that the tooth preparation can be validated by the dental preparation guide; and e: creating a virtual preparation guide surface by combining the virtual validation surface and at least part of the surface of the 3D digital representation of the remaining set of teeth.

It remains a problem to provide a procedure, user interface, and system for creating digital restoration designs where the operator does not need to set the restoration margin line manually.

Compendium

The present invention is described in appended claims 1 to 11 and is described below.

A procedure is described for creating a digital restoration design using a computer to fabricate a dental restoration for one or more of a patient's teeth, in which the dental restoration is a superior restoration for raising the occlusal table. of the patient's teeth,

where the procedure includes:

- obtain a 3D digital representation of the patient's unprepared teeth;

- obtaining a set of one or more digital anatomies of the teeth that express the desired objective shape of the patient's teeth;

- arranging the digital anatomies of the teeth expressing the desired objective shape of the patient's teeth and the digital 3D of the unprepared teeth of the patient according to a relative arrangement;

- obtain a restoration margin line of the digital restoration design, at least partially, from an intersection of the 3D digital representation and the digital anatomies of the teeth that express the desired objective shape of the patient's teeth lift the bite of the patient; Y

- create the digital restoration design that includes a restoration margin line where the restoration margin line is obtained, at least partially, from an intersection of the 3D digital representation of the patient's unprepared teeth and the Digital anatomies of the teeth that express the desired objective shape of the patient's teeth.

The described procedure, system, and user interface provide the advantage over the prior art that digital restoration designs can be created without the operator needing to set the restoration margin line manually or at least with minimal manual interaction.

Therefore, a digital restoration design can be created for fabrication of a restoration or superior veneer without the operator needing to manually set the restoration margin line of the restoration or superior veneer.

A physical dental restoration based on the digital restoration design can be fabricated and the dental restoration can be placed on the patient's teeth. In the context of the present invention, the phrases "dental restoration" and "fabricated dental restoration" refer to a dental restoration fabricated from the created digital restoration design.

The purpose of the dental restoration influences its objective shape and, therefore, the digital design of the restoration. The purpose is to lift the patient's bite so that the target shape is directed toward increasing the length of the teeth to restore the patient's original occlusal table. Preferably, a reasonably attractive shape of the teeth is maintained when the upper restoration is seated in the mouth.

In the context of the present invention, the phrase "lift the patient's bite" refers to the situation in which the occlusal table of the teeth is displaced coronally, that is, further from the roots of the gums / teeth, when the dental restoration sits on the teeth.

The purpose of the dental restoration may also be to improve the aesthetic appearance of the patient's tooth set, so that the target shape is directed toward an aesthetically appealing shape and arrangement of dental restorations. A veneer is an example of such a dental restoration.

In the preferred relative arrangement, the digital anatomies of the teeth and the 3D digital representation are arranged with each other according to a correct anatomical arrangement.

This provides the advantage that various digital operations, such as boolean subtraction of the 3D digital representation of the digital anatomies of the teeth when creating the digital restoration design. Furthermore, it provides that the digital anatomies of the teeth can be viewed together with the digital representation of the corresponding teeth, that is, the teeth on which the fabricated dental restoration (s) will be located.

Obtaining the restoration margin line of the digital anatomies of the teeth with the digital anatomies of the teeth and the 3D digital representation arranged according to the preferred relative arrangement provides that the creation of the dental restoration design can be made highly automatic. The restoration margin line can be determined automatically without the need for the operator to use the time to manually define the restoration margin line.

A patient's tooth can be prepared for a crown restoration by grinding the tooth material making room for the crown restoration. The prepared tooth is often referred to as a dental stump since its size is significantly smaller than that of the unprepared tooth.

Superior restorations are frequently used when the occlusal table of the patient's teeth is seriously worn. The upper restoration is shaped to settle on the top of the teeth where the patient's bite rises. Therefore, there is often no need to prepare the tooth by grinding substantial amounts of the tooth material. The same is true for so-called minimal preparation veneers that comprise a relatively thin layer of restorative material shaped to cover the labial and oral surfaces of the teeth in order to improve the aesthetics of the teeth.

For superior restorations, it may be advantageous to grind a small portion of tooth material, eg. ex. to remove material from a dead tooth or to provide good adhesion of the superior restoration to the teeth. Such minimally prepared teeth are still referred to as unprepared teeth in this application.

In the case of a minimal preparation veneer, a thin layer of tooth material can be removed from the buccal / labial surface of the tooth to improve the adherence of the veneer when it settles on the teeth. This is however preferably a very thin layer such as a layer with a thickness of less than about 1 mm. Such minimally prepared teeth are also referred to as unprepared teeth in this application.

That is, in the context of the present invention, the phrases "teeth not prepared" and "teeth in their unprepared state" refer to teeth that have undergone no or minimal preparation.

When the dental restoration fabricated from the digital restoration design is disposed on the patient's teeth, the effective shape of the teeth is determined, at least partially, by the shape of the dental restoration. In the context of the present invention, the phrase "effective form" is used to describe the outer surface of the tooth / restoration assembly obtained when the dental restoration sits on the patient's teeth. For a superior restoration, the tooth / restoration set occlusal table is defined, at least partially, by the exterior shape of the dental restoration, while for a minimal preparation veneer, the exterior shape of the dental restoration defines at least partially, the lip / buccal surface of the tooth / restoration set.

The effective shape of the teeth with the mounted dental restoration is determined in part by the shape of the digital anatomies of the teeth and in part by the preferred relative arrangement of the digital anatomies of the teeth and the digital 3D rendering. The digital anatomy of the teeth thus expresses a desired objective shape of the part of the patient's teeth covered by the fabricated dental restoration.

In some embodiments, the method comprises detecting a collision line from the intersection of the 3D digital representation and the digital anatomies of the teeth.

In some embodiments, the restoration margin line of the digital restoration design is derived from the detected collision line.

Detection of the intersection or collision line and obtaining the restoration margin line from the detected intersection or collision line are preferably performed by computer-implemented algorithms executed, eg. ex. in a microprocessor. This provides the advantage that the operator does not need to manually define the restoration margin line of the dental restoration or at least an initial assumption of the restoration margin line so that the process design can be accelerated. This advantage is obtained, eg. ex. in cases where there is no tooth preparation line to which the restoration margin line needs to be precisely matched. This is, for example, the case when the fabricated dental restoration is to be disposed on a patient's unprepared teeth. In contrast, when the dental restoration is a crown or bridge for a prepared tooth set, the restoration margin line should preferably exactly match the tooth preparation line to avoid, e.g. ex. a grove in the transition between the dental restoration and the prepared tooth that causes discomfort and the risk of bacteria being trapped.

In some cases, the operator may choose to make slight modifications to the obtained restoration margin line, but this is often not necessary. An example of such a modification is smoothing the restoration margin line to provide a smooth restoration margin line that is easier to manufacture. In some embodiments, the restoration margin is obtained, at least partially, from a curve defined on the 3D digital representation of the patient's unprepared teeth, where the defined curve is smoother than the intersection, i.e., the Defined curve has less variation than the intersection along the longitudinal axis of the teeth in the 3D rendering of the unprepared teeth.

Using a smooth curve to define the restoration margin line provides the advantage that the dental restoration can be more easily fabricated from the digital restoration design. A dental restoration with a very irregular margin line using CAM equipment will be more difficult to perform than a restoration with a smooth margin line.

The curve can be defined by an operator using a pointed tool to draw the curve on a 3D digital representation display of the unprepared teeth in a user interface. If the intersection is illustrated in the user interface, the operator can use the intersection as a guide and draw the curve, e.g. ex. as an average of the intersection,

The smooth curve can also be defined by applying a computer-implemented smoothing algorithm to the intersection.

This provides the advantage that even less user interaction is required to establish the restore margin line.

Smoothing can also be applied to the restorative margin line obtained by making the restoration margin line smooth on digital tooth surface anatomies.

This has the same advantage as obtaining the restoration margin line from a smooth curve, that is, the dental restoration can be more easily fabricated from the digital restoration design.

In some embodiments, the portion of the digital anatomy of the teeth on the basis of which the outer surface of the digital restoration design is formed by the defined curve, such as projecting the curve onto the digital anatomy of the teeth.

When the smooth curve is defined on the 3D digital representation of the patient's unprepared teeth, some parts of the curve may shift from the digital anatomy of the teeth. In such cases, the restoration margin line can be obtained by projecting the curve onto the digital anatomies of the teeth.

The restoration margin line obtained divides the digital anatomies of the teeth into a coronal part and a cervical / apical part, where the coronal part is used to form the digital restoration design.

In some embodiments, the method comprises digitally removing portions of the cervical / apical digital anatomy of the teeth from the restoration margin line and thus using the truncated digital anatomy of the teeth to create the digital dental pattern.

In the context of the present invention, the phrase "element 1 that is coronal to element 2" refers to the situation where element 1 is closer to the occlusal surface / incisal edge of a tooth than element 2. In In the context of the present invention, the phrase "element 1 that is cervical / apical to element 2" refers to the situation where element 1 is closer to the root part of the tooth, ie where element 2 it is closer to the occlusal surface / incisal edge of a tooth than element 1.

Using the part of the digital anatomy of the coronal teeth to the restoration margin line when creating the digital restoration design means that it is the part of the digital anatomy of the teeth that extends from the restoration margin line and on the occlusal surface / incisal edge used in the creation of the digital restoration design. The restoration margin line thus separates the coronal and cervical parts from the first digital anatomies of the teeth.

The restoration margin line can also separate the coronal and cervical portions of the tooth portion of the 3D digital representation and, in some embodiments, the coronal portion of the 3D digital representation is limited by the restoration margin line. . In some embodiments, the method comprises digitally deleting portions of the digital 3D cervical representation to the restoration margin line and thus using the truncated 3D digital representation when creating the digital dental design.

In some embodiments, creating the digital restoration design comprises forming an interior surface and an exterior surface of the digital restoration design, where the interior and exterior surfaces are based on coronal portions of the digital 3D representation and digital anatomies of the teeth, respectively. In some embodiments, the coronal portion of the digital anatomy of the teeth is limited by the restoration margin line.

In some embodiments, an exterior surface of the digital restoration design is formed, at least partially, based on portions of the digital anatomies of the coronal teeth at the restoration margin line.

The exterior surface of the digital restoration design shapes the exterior surface of the fabricated dental restoration and therefore determines the effective shape of the tooth / restoration assembly obtained when the fabricated dental restoration sits on the teeth.

In some embodiments, an interior surface of the digital restoration design is created, at least partially, from portions of the 3D digital representation of the unprepared teeth coronal to the restoration margin line.

The interior surface of the digital restoration design is configured to look at existing teeth when the fabricated dental restoration sits on the patient's teeth.

The inner and outer surfaces can be created from the coronal portions simply by copying them, or by copying and modifying them according to the experience and preferences of the operator, e.g. ex. shifting the copied surface.

In some embodiments, the interior surface of the digital dental design is created, at least partially, by copying the coronal 3D digital representation portion to the restoration margin line. In some cases, an offset is applied to the copied surface for, eg. ex. make room for the cement used to bond the dental restoration to the tooth / teeth,

In some embodiments, the outer surface of the digital dental design is created, at least partially, by copying the portion of the digital anatomy of the coronal teeth to the restoration margin line.

In some embodiments, the creation of the digital restoration design comprises a Boolean subtraction of the 3D digital representation of the digital anatomies of the teeth.

Boolean subtraction can be performed after the restore margin line has been determined and optionally smoothed.

The intersection of the digital 3D representation and the digital anatomies of the teeth can be automatically defined in the Boolean subtraction. Creating the digital restoration design using such a Boolean subtraction has the advantage that the restoration margin line (obtained from the intersection) can be determined automatically.

The shape and position of the restoration margin line depends on the digital anatomy of the teeth, the 3D digital representation, and the preferred relative arrangement.

Obtaining the restoration margin line may comprise a step of smoothing the intersection and / or smoothing the restoration margin line, e.g. ex. in the event that boolean subtraction results in an irregular restoration margin line that may hinder the fabrication of the dental restoration.

In some embodiments, at least part of the interior surface of the digital restoration design is created, at least partially, by boolean subtraction of the 3D digital representation of the digital anatomies of the teeth.

A Boolean subtraction of a first solid digital structure from a second solid digital structure provides for a third solid digital structure to be generated where the third solid digital structure is shaped according to the second solid digital structure where the parts shared with the first solid digital structure are removed.

When the 3D digital representation is subtracted from the digital anatomies of the teeth, both are preferably expressed as solid digital structures. That is, if the obtained 3D digital representation is not yet in the form of a solid digital structure, the procedure may comprise adapting the 3D digital representation to become a solid digital structure expressing the shape of the patient's teeth. When the 3D digital representation is initially an open surface, a closing surface can be generated, e.g. ex. using a tracing procedure, where adding the closure surface to the open surface of the 3D digital rendering provides it to become a solid digital structure. The same is true for the digital anatomies of the teeth, where if the digital anatomies of the teeth are not yet in the form of a solid digital structure, the procedure may involve adapting them to convert them into solid digital structures.

Boolean subtraction from solid digital structures may correspond to the determination of their relative complement, so that the digital restoration design resulting from Boolean subtraction is the part of the digital anatomy of teeth that is not shared with the digital representation in 3D. Thus, the inner surface created from the digital restoration design is shaped according to the shape of the corresponding part of the 3D digital representation, while the outer surface of the digital restoration design is shaped according to the shape of the digital anatomies of the teeth. Therefore, the interior surface of the digital restoration design is created, at least in part, by determining the relative complement of the 3D digital representation in the digital anatomies of the teeth.

Using the Boolean subtraction approach, the restoration margin line is automatically defined at the same time as the interior and exterior surfaces of the digital restoration design are formed.

A displacement can be provided to the created interior surface of the digital restoration design to ensure space for the cement between the patient's teeth and the fabricated dental restoration.

In some embodiments, the method comprises establishing or determining an insertion direction of the dental restoration.

This provides the advantage that the digital restoration design can be optimized for a specific insertion direction and / or that it can be ensured that the fabricated dental restoration can actually be inserted into the patient's teeth.

In some embodiments, the method comprises adjusting the digital anatomy of the teeth, such as adjusting the digital anatomy of the teeth to provide a better fit of the dental restoration to the patient's teeth.

This is often required to provide that the digital restoration design is not only the desired shape but also the right size for the patient. Also collisions with the opposing teeth can be optimized by adjusting the digital anatomies of the teeth.

In some embodiments, placement of the digital anatomy of the teeth on the 3D digital representation of the unprepared teeth, adjustment of the direction of insertion, and adjustment of the digital anatomy of the teeth is an iterative process toward placement, the optimal size and shape of the digital anatomies of the teeth in relation to the 3D digital representation of the unprepared teeth.

In some embodiments, the method comprises examining the digital restoration design against one or more minimum thickness criteria to identify any problem regions.

A problem region may be a region of the digital restoration design where the thickness is less than that specified by the minimum thickness criteria. In the dental restoration fabricated from the digital restoration design, the corresponding region will be so thin that the dental restoration will be brittle and / or difficult to fabricate.

Examining the digital restoration design against one or more minimum thickness criteria provides the advantage that the operator can be warned that the current digital restoration design will provide a fragile dental restoration.

In some embodiments, the method comprises adjusting the digital restoration design in the problem regions to provide that the minimum thickness criteria are met in these regions.

This has the advantage that the dental restoration made from the digital restoration design will be robust and free of fragile regions and / or that the restoration can be more easily fabricated using Computer Aided Manufacturing (CAM) equipment.

In some embodiments, the adjustment comprises:

- increase the thickness of the digital restoration design in the problem region so that the minimum thickness criteria are met, and / or

- digitally remove the problem region from the digital restoration design.

Both increasing the thickness of the digital restoration design and digital removal of the problem region provide the advantage that the dental restoration fabricated from the digital restoration design can be free of fragile regions where it could otherwise rupture and / or the restoration can be more easily fabricated with Computer Aided Manufacturing (CAM) equipment.

In some embodiments, the method comprises defining a displacement surface by displacing at least a portion of the 3D digital representation of the patient's unprepared teeth by a distance according to the minimum thickness criteria. The displacement is directed outward relative to the surfaces of the digital 3D rendering. For example, if a minimum thickness criterion imposes a minimum thickness of 0.2 mm, the displacement surface can be formed by displacing the 3D digital representation by 0.2 mm.

The displacement surface can be used when examining the digital restoration design to identify problem regions where the minimum thickness criteria are not met. This can be done by identifying the portions of the digital anatomy of the teeth or the portions of the created digital restoration design that lie between the 3D digital representation and the displacement surface. Such portions will not meet the minimum thickness criteria.

The displacement surface can also be used in adjusting the digital restoration design to provide that minimum thickness criteria are met in all regions. Problem regions of digital restoration design can eg. ex. Snap-fit on the displacement surface, i.e. be shaped to follow the displacement surface, thus providing that the thickness of the digital restoration design is increased to a level where the minimum thickness criteria are also met in those regions. That is, in some embodiments, increasing the thickness of the digital restoration design in the region Problems include forming a displacement surface from the 3D digital representation, where the displacement is determined from the minimum thickness criteria.

The scroll surface can be used initially to assess for problem regions. If problem regions are found, the displacement surface can be used for adjusting the digital restoration design, for example, by modifying the digital restoration design to follow the displacement surface, at least in part, of the problem regions.

In some embodiments, the adjustment comprises shaping the digital restoration design according to the displacement surface in at least part of the problem regions.

In some embodiments, the examination involves identifying problem regions as the regions of the digital restoration design where the digital restoration design lies between the displacement surface and the 3D digital representation.

In some embodiments, the digital restoration design is for fabrication of the dental restoration by milling, and the method comprises adjusting the digital restoration design to provide compensation for the bur.

In the context of the present invention, the phrase "provide drill compensation" refers to the case where the digital restoration design is adjusted to take into account the shape of the drill to be used in the fabrication of the dental restoration.

When the tip of the burr has a curvature, it cannot form, e.g. ex. a 90 degree flex. When trying to form tight flexes, some material will remain. For a dental restoration with an interior surface shaped to match the occlusal surface of the teeth (not prepared), this remaining material may collide with the tooth and prevent the dental restoration from settling on the tooth.

In some embodiments, bur compensation is provided by introducing one or more indentations into the digital restoration design.

This is advantageous since the indentation can be arranged so that any remaining material after drilling does not prevent the dental restoration from settling on the tooth.

In some embodiments, the size of the indentation cross section is chosen to be greater than or equal to the diameter of the drill to be used in the fabrication of the dental restoration. For an indentation with a circular cross section, the size of the cross section is the diameter of the indentation.

In some embodiments, the digital restoration design is digitally fitted at least to the inner surface of the digital restoration design. That is, the bur offset is provided on the inside surface of the digital restoration design.

This provides the advantage that the fabricated dental restoration can settle on unprepared teeth. The offset of the burr can in some cases make the fabricated dental restoration fragile in the indentation. Accordingly, in some embodiments, the position of the indentation is determined based on the thickness of the digital restoration design, that is, the distance from the inner surface to the outer surface of the digital restoration design. This can be done by determining the expected thickness of the digital restoration design and / or the fabricated dental restoration. This expected thickness of the digital restoration design and the fabricated restoration may be different due to a curved tip of the bur. If the expected thickness with the indentation formed at one position is below a lower limit, the expected thickness can be determined for one or more other positions of the indentation and the position of the indentation can be decided from there. The expected thickness distribution for the relevant parts of the digital restoration design can also be calculated and visualized using e.g. ex. a color map indicating where the indentation can be placed to compensate for the finite size of the bur without making the dental restoration brittle.

Such burr compensation can be performed regardless of how the digital restoration design is created, i.e. also without the restoration margin line being determined from an intersection of the digital anatomies of the teeth and a digital representation in 3D rendering of the patient's unprepared teeth. In some embodiments, the method comprises adjusting the curvature of the digital restoration design on the restoration margin line to match the curvature of the 3D digital representation of the patient's teeth.

Matching the curvatures of the digital restoration design and 3D digital representation on the restoration margin line can improve the appearance of the tooth / restoration assembly. A large mismatch in curvature can make the interface between the dental restoration and the teeth clearly visible. Adjusting the curvature provides a smoother and less visible transition from the teeth to the dental restoration at the restoration margin line.

The digital restoration design is for the fabrication of a set of upper teeth to lift the occlusal table from the patient's teeth.

The objective shape corresponds to a lifting of the occlusal surface / incisal edge of the teeth. The effective size of the teeth increases along the longitudinal axis of the teeth when the fabricated dental restoration sits on the teeth. The desired objective shape of the patient's teeth expressed by the digital anatomies obtained from the teeth is such that the effective size of at least one tooth increases when the fabricated restoration is seated in the teeth.

The upper teeth can be a temporary restoration used by the patient for a period of time in which the patient's muscles are trained for the raised bite. This may apply to patients who have problems with the temporomandibular joint (TMJ) and where the occlusal surface of e.g. ex. the teeth of the mandibular jaw must be raised to treat the problem. After a period of time, p. ex. Some months, the dentist evaluates if the raised bite is adequate and solves the TMJ problems. If the temporary restoration has been shown to be properly shaped to provide the necessary elevation of the patient's bite, a permanent restoration can be fabricated based on the same digital restoration design used for the temporary restoration.

In some embodiments, obtaining the digital anatomies of the teeth involves selecting a set of teeth from the library.

This has the advantage that the digital anatomy of the teeth can be obtained faster than when the operator himself designs the surfaces of the digital anatomy of the teeth.

In some embodiments, obtaining the digital anatomies of the teeth comprises copying an occlusal surface from the 3D digital representation and forming the digital anatomies of the teeth based on the copied occlusal surface.

This can be done, eg. ex. displacing one or more occlusal and / or incisal surfaces of the 3D digital representation and digitally forming a connecting surface configured to connect the displacement surfaces and the remaining part of the 3D digital representation.

Copying the occlusal surface of existing teeth to the digital anatomy of the teeth can be advantageous when the existing teeth have an acceptable shape but the teeth are short, so that the patient's bite must be lifted.

A procedure for creating a digital restoration design for the fabrication of a dental restoration for one or more of a patient's teeth is described, where minimal manual interaction is required when establishing the restoration margin line, where the procedure comprises:

- obtain a 3D digital representation of the patient's unprepared teeth;

- obtain a set of one or more digital anatomies of the teeth;

- arranging the digital anatomies of the teeth and the digital representation in 3D according to a preferred relative arrangement; Y

- create an inner surface and an outer surface of the digital restoration design, where the inner and outer surfaces are based on coronal portions of the 3D digital representation and of the digital anatomies of the teeth, respectively.

In some embodiments, the user interface comprises a virtual push button configured to create the digital restoration design when activated.

The digital restoration design can be created using a method according to any of the embodiments. For example, the digital restoration design can be created based on a Boolean subtraction that offers the opportunity to create the digital restoration design with minimal manual interaction by setting the restoration margin line of the digital restoration design.

In some embodiments, the user interface is configured to be displayed to an operator using a display unit and to allow an operator to enter data and make choices presented on the user interface using a computer keyboard or a computer mouse.

In some embodiments, the user interface comprises a data entry section for entering data related to, e.g. ex. if the digital restoration design is to be created using boolean subtraction.

In some embodiments, the user interface is configured to display the intersection between the 3D digital representation and the digital anatomies of the teeth.

In some cases, the dental restoration fabricated from the digital restoration design is a temporary dental restoration for the patient's unprepared teeth, such as a superior temporary restoration, worn by the patient over a period of time, e.g. ex. to lift your bite and train your muscles towards the raised bite. After this period, the dentist may choose to prepare the patient's teeth for a permanent restoration, e.g. ex. grinding teeth material.

The digital restoration design for temporary and permanent restorations is referred to below as the first and second digital restoration designs, respectively.

The first digital restoration design created for temporary dental restoration can also be used later in the processes to create a second digital restoration design for permanent dental restoration. For a superior restoration, the second dental restoration is preferably shaped so that it can sit on the prepared tooth and its occlusal table is located according to the occlusal table of the superior temporary restoration.

A procedure is described, which does not form part of the claimed invention, to create a first digital restoration design for the unprepared teeth of a patient and a second digital restoration design for the teeth after they have been prepared, where the procedure includes:

- obtain a first 3D digital representation of the patient's unprepared teeth;

- obtain a set of one or more digital anatomies of the teeth;

- arranging the digital anatomies of the teeth and the first 3D digital representation according to a preferred relative arrangement;

- creating a digital restoration design comprising a restoration margin line, where the restoration margin line is obtained, at least partially, from an intersection of the 3D digital representation and the digital anatomies of the teeth;

- obtain a second digital 3D representation of the patient's prepared teeth;

- identify a tooth preparation line in the second digital 3D representation; Y

- creating a second digital restoration design based on the first digital restoration design and / or on the digital anatomies of the teeth, where the creation comprises generating a connection surface configured to connect the tooth preparation line and the first design of digital restoration and / or digital anatomy of teeth.

The second 3D digital representation is related to the shape of the patient's teeth after the tooth material has been removed to prepare the teeth for permanent dental restoration. When the dental restoration is a set of upper teeth, the temporary dental restoration is used to train the muscles of the patient's jaw and to test whether the occlusal table of the temporary restoration is suitable for the patient's occlusion. When creating the second digital restoration design for permanent dental restoration, you preferably take into account the first digital restoration design, either by copying it directly or taking it as a starting point that is adjusted based on the patient experience using the temporary teeth superior.

The connecting surface and part of the first digital restoration design and / or in the digital anatomies of the teeth form at least part of the outer surface of the second digital restoration design. The exterior surface of the second digital restoration design thus ends at the tooth preparation line that becomes the restoration margin line of the permanent dental restoration.

In some embodiments, the interior surface of the second digital restoration design is created, at least partially, from the portion of the second 3D digital representation corresponding to the prepared teeth that the permanent restoration will apply to the patient's mouth. This may involve copying the relevant part of the second 3D digital representation and optionally applying an offset to make room for the cement used to bond the permanent dental restoration to the prepared teeth. This provides that the second dental restoration fabricated from the second digital restoration design can be placed on the prepared teeth.

The first digital restoration design can be created based on the first 3D digital representation and digital anatomies of the teeth using any of the described embodiments to do so.

A method, not forming part of the claimed invention, is described for creating a second digital restoration design for manufacturing a dental restoration for one or more of a patient's prepared teeth based on a first created digital restoration design for the patient's unprepared teeth, where the procedure includes:

- get a first digital restoration design;

- obtain a second digital 3D representation of the patient's prepared teeth;

- identify a tooth preparation line in the second digital 3D representation; Y

- creating the second digital restoration design, where the creation comprises generating a connection surface configured to connect the tooth preparation line and the first digital restoration design.

In some embodiments, the first digital restoration design is for the fabrication of a dental restoration configured to augment the size of at least one of the patient's unprepared teeth, such as for fabrication of a set of upper teeth.

In some embodiments, the connection surface contacts the first digital restoration design on a contact line that is disposed coronally to the restoration margin line of the first digital restoration design. The part of the first digital restoration design coronal to the contact line preferably forms part of the outer surface of the second digital restoration design, while the portion of the connecting surface between the contact line and the tooth preparation line forms another portion of the outer surface.

Brief description of the drawings

The foregoing and / or additional objects, features, and advantages of the present invention will be elucidated below through the following illustrative and non-limiting detailed description of the embodiments of the present invention, with reference to the accompanying drawings, in the what:

Fig. 1 shows exemplary workflows for the method according to the invention.

Fig. 2 shows a schematic of the teeth in one of the patient's jaws.

Fig. 3 shows a schematic of a cross section of the patient's teeth.

Fig. 4 shows a schematic of a fabricated superior restoration.

Fig. 5 illustrates intersection detection to create the digital restoration design.

Fig. 6 illustrates the creation of a digital restoration design using a Boolean subtraction.

Fig. 7 illustrates the fit of the digital restoration design to meet a minimum thickness criterion.

Figs. 8 and 9 illustrate the fit of the digital restoration design to provide compensation for the bur. Fig. 10 illustrates the curvature match of the digital restoration design on its restoration margin line.

Fig. 11 shows the steps in a workflow to create a second digital restoration design for a permanent upper restoration, which is not part of the claimed invention.

Fig. 12 shows schematics of a second digital restoration design for a permanent dental restoration, which is not part of the claimed invention.

Fig. 13 shows a schematic of a system.

Fig. 14 shows a schematic of a user interface.

Fig. 15 shows part of a screenshot of a user interface.

Fig. 16 shows a smooth curve formed based on the intersection.

Detailed description

In the following description, reference is made to the accompanying figures, which illustrate how the invention may be practiced.

Fig. 1 shows examples of workflows according to embodiments of the method according to the invention.

Fig. 1A illustrates a workflow 100 according to an embodiment of the invention.

In step 101, a 3D digital representation of the patient's unprepared teeth is obtained. 3D digital representation can be obtained, eg. ex. using an intraoral 3D scanner, such as the TRIOS intraoral scanner provided by 3shape A / S, where the teeth are scanned directly into the patient's mouth. The 3D digital representation can also be obtained by scanning an impression of the teeth or by scanning a physical model of the teeth obtained using the impression.

The digital 3D representation may be of the complete set of teeth of the patient or a part of the set of teeth, such as a part of the teeth in the upper and / or lower jaw. Digital 3D rendering provides information related to at least the geometry of the teeth.

In step 102, a set of one or more digital anatomies of the teeth is obtained. Digital tooth anatomies are a set of library teeth selected from a library of digital tooth templates and express the desired target shape of the patient's teeth when the dental restoration is seated in them. The target shape is such that the size of at least one tooth increases when the fabricated dental restoration is disposed on the teeth.

When the patient has overused the teeth so that the length of the teeth is significantly reduced, the dentist may choose to design and fabricate a superior restoration for the patient. The upper restoration is designed to restore the original length of the teeth and thus the original occlusal table of the teeth. This is called lifting the patient's bite.

If the occlusal table of the patient's teeth is properly shaped (eg has anatomically acceptable occlusion with the opposing teeth) but the teeth are too short, the dentist may

occlusal of existing teeth in the digital anatomy of teeth. This can be provided in various ways, such as by displacing the one or more occlusal and / or incisal surfaces of the 3D digital representation and digitally forming a connecting surface configured to connect the displacement surfaces and the remaining portion of the digital representation in 3D.

When the patient is not satisfied with the appearance of their teeth, they may want to have a veneer designed and manufactured for their teeth. The patient may still have all of their teeth in their original, unprepared shape, but wants a more attractive smile. The digital restoration design can be created so that the veneer fabricated from it can settle on the unprepared teeth that cover parts of the oral / lip surfaces of the teeth where it provides improved smile aesthetics.

Antagonistic teeth can be considered when designing digital tooth anatomies. This may include analysis of occlusion of the digital anatomies of the teeth with a 3D digital representation of the opposing teeth using, eg. ex. a virtual articulator to mimic the relative movement of the patient's jaws in a bite.

In step 103, the digital anatomies of the teeth and the 3D digital representation are arranged with each other according to a preferred relative arrangement.

The 3D digital representation can be arranged / expressed in a coordinate system, such as the coordinate system of a virtual articulator used to digitally analyze the relative movement of the patient's jaws and teeth during a bite. Organizing the digital anatomies of the teeth and the 3D digital representation of each other can include expressing them in the same coordinate system.

One way to arrange the digital anatomies of the teeth and the 3D digital representation of each other is to determine a transformation matrix to represent the two in the same coordinate system. This may be, e.g. ex. a transformation matrix to represent the digital anatomies of the teeth in the coordinate system of the digital representation in 3D, or vice versa. They can also be transformation matrices to represent the two in another coordinate system, such as the coordinate system of a virtual articulator used to digitally analyze the relative movement of the patient's mandibular and maxillary teeth during the movement of the jaw.

When the digital anatomies of the teeth and the 3D digital representation are expressed in the same coordinate system, they can also be visualized to an operator using, e.g. ex. a computer screen.

The digital anatomies of the teeth are arranged in relation to the 3D digital representation according to the way in which the fabricated dental restoration is to be placed in relation to the patient's unprepared teeth. For a set of upper teeth, the preferred relative arrangement of the digital anatomies of the teeth and the 3D digital representation is such that the occlusal table of the digital anatomies of the teeth is located according to the desired location of the occlusal table of the dental restoration in relation to the patient's teeth. An insertion direction is also established or determined for the insertion of the dental restoration into the patient's unprepared teeth. With knowledge of the insertion direction, it can be verified that the digital restoration design is such that the fabricated dental restoration can actually be placed on the patient's unprepared teeth.

In step 104 the digital restoration design is created. The digital restoration design comprises a restoration margin line and the procedure comprises obtaining the restoration margin line from an intersection of the 3D digital representation and the digital anatomies of the teeth. The digital restoration design is created with minimal user interaction to establish the restoration margin line of the dental restoration, i.e. a dentist or dental technician performing the procedure needs to spend less or no time establishing the margin line restoration.

Next, the digital anatomies of the teeth have been loaded from a library of anatomy templates, an adjustment of the digital anatomies of the teeth is often required, e.g. ex. to provide a better fit of the dental restoration on the patient's teeth.

The direction of insertion, the arrangement and the adjustment of the digital anatomies of the teeth can be carried out in an iterative process to obtain the most satisfactory result.

Fig. 1B illustrates the steps in a workflow 105 to create the digital restoration design based on the intersection.

At step 106, the intersection between the 3D digital representation and the digital anatomies of the teeth is determined using computer-implemented surface-to-surface intersection algorithms that, e.g. ex. they return a 3D spline that expresses the shape and position of the intersection in relation to the 3D digital representation and / or in relation to the digital anatomies of the teeth.

In step 107, a restoration margin line of the digital restoration design is obtained from the intersection.

This can be done by simply copying the intersection so that the restore margin line is automatically obtained without the need for an operator to manually configure it. In some cases, the operator may choose to make slight modifications to the intersection before obtaining the restoration margin line.

If the intersection is very irregular, the operator may decide to define a smooth curve on the 3D digital representation of the unprepared teeth by following the overall shape of the intersection, but avoiding the peaks and valleys at the irregular intersection. The restoration margin line is subsequently derived from the smooth curve and the created digital restoration design will have a margin line that can be more easily fabricated using CAM equipment.

In the 3D digital representation of unprepared teeth, the restoration margin line separates a coronal portion and a cervical portion from the 3D digital representation, so that the coronal portion of the 3D digital representation is limited by the line of restoration margin. At step 108, an interior surface of the digital restoration design is formed based on the coronal portion of the 3D digital representation. In digital tooth anatomies, the restoration margin line separates a coronal portion and a cervical portion of the digital tooth anatomy, so that the coronal portion of the digital tooth anatomy is limited by the margin line. restoration. At step 109, an outer surface of the digital restoration design is formed based on the coronal portion of the digital anatomies of the teeth.

With the exterior and interior surface of the digital restoration design formed, a solid digital structure can be formed for the digital restoration design by closing any gaps between the interior and exterior surface at the restoration margin line, e.g. ex. forming a connection surface using a computer-implemented mapping algorithm.

Fig. 1C illustrates the steps of a workflow 111 to create the digital restoration design using a Boolean subtraction.

At step 112, the 3D digital representation is adapted to become a solid digital structure. The digital representation in 3D can be, e.g. ex. a polygonal mesh provided by a 3D scanner and provides information related to the geometry / shape of the patient's teeth and possibly the surrounding gingiva. From this polygonal mesh a solid digital structure can be formed for 3D digital representation. The formed solid digital framework can be used in Constructive Solid Geometry (CSG) to create the digital restoration design using e.g. ex. a computer-implemented boolean subtraction algorithm.

In some cases, the 3D digital representation obtained from the 3D scanner is already a solid digital structure, so step 112 is not required.

At step 113, the digital anatomies of the teeth adapt to become one or more solid digital structures. Often, the digital anatomies of the teeth selected from a library of teeth already have the shape of one or more solid digital structures, so step 113 is not required.

At step 103, the digital anatomies of the teeth and the 3D digital representation are arranged according to a preferred relative arrangement as described above in connection with Fig. 1A.

In step 114 the insertion of the dental restoration is adjusted and in step 115 the digital anatomies of the teeth are adjusted. These adjustments are made to obtain the best design of the dental restoration with respect to the shape and function of the dental restoration and to ensure that the fabricated restoration can be inserted into the teeth.

At step 106, the intersection of the digital anatomy of the teeth and the 3D digital representation is detected as also described above in connection with Fig. 1A.

The operator may choose to iteratively adjust the relative arrangement, insertion direction, and digital anatomy of the teeth until a satisfactory result is obtained. Detection of the intersection can be part of said iterative loop or the intersection can be detected after the loop.

At step 116, the digital restoration design is created by boolean subtraction of the digital 3D representation of the digital anatomies of the teeth.

The inner surface of the digital restoration design, that is, the surface that the fabricated dental restoration will look at the patient's teeth, is shaped according to the surface of those teeth. A gap can be inserted to leave some room for an adhesive agent, such as cement, which is used to secure the dental restoration to the teeth.

Boolean subtraction corresponds to determining the relative complement of the digital representation in 3D in the digital anatomies of the teeth. The resulting digital restoration design is therefore the part of the digital anatomy of the teeth that is not shared with the 3D digital representation.

The outer surface of the digital restoration design is defined by the outer surface of the digital anatomy of the teeth.

Fig. 1D illustrates the stages of a workflow 117 where the restoration margin line is derived from a smooth curve.

In steps 103 and 106, the digital anatomies of the teeth and the digital 3D representation are arranged according to a preferred relative arrangement and the intersection is detected as also described above in connection with Fig. 1A.

Often in situations where the intersection is very uneven, the operator will decide that it will be difficult to fabricate a dental restoration from a digital restoration design with such a restoration margin line. In such cases, the operator may choose to form a smooth curve on the 3D digital representation of the unprepared teeth based on the intersection detected in step 118 and then obtain the restoration margin line from the smooth curve in the step 119. The restoration margin line can be defined, eg. ex. projecting the smooth curve into the digital anatomies of the teeth.

At step 116, the digital restoration design is created by boolean subtraction of the 3D digital representation from the digital anatomies of the teeth as described in connection with Fig. 1C.

Fig. 2 shows a schematic of the teeth in one of the patient's jaws.

The diagram shows teeth 220 not prepared with the anterior teeth at the top of the figure and the molars at the bottom. A cross section plane is defined by the line A-A 'that crosses a tooth 221 and the normal to the occlusal plane of the set of teeth, that is, the plane of the cross section is perpendicular to the patient's occlusal plane.

Figures 3 to 10 show diagrams of 3D digital representations of the unprepared teeth, digital restoration designs and different surfaces represented as cross sections in a plane such as that defined in Figure 2.

Fig. 3 shows a diagram of a cross section 325 of the patient's teeth in the AA 'plane seen in Fig. 2. The complete line shows the shape of the unprepared teeth in their current state 327, while the line dotted shows the original shape of 329 teeth. The teeth are seriously worn, so the current occlusal table 328 is much lower than the original occlusal table 330. This causes discomfort to the patient and unnatural tension in the active muscles during, eg. ex. chewing.

Fig. 4 shows a schematic of a tooth / restoration assembly 432 with a fabricated upper restoration disposed on the worn tooth illustrated in Fig. 3.

The upper restoration 433 is designed to lift the occlusal table from the unprepared tooth 427. It has an inner surface 435 shaped to apply the surface of the unprepared tooth 427 and an outer surface 436 shaped to apply the antagonist teeth when the patient bites. The upper restoration 433 increases the length of the patient's teeth and when the patient uses the restoration, the muscles become accustomed to the raised bite defined by the upper tooth set.

In a dental restoration fabricated from the digital restoration design using direct digital fabrication techniques such as CAM drilling, the restoration margin line of the dental restoration is defined by the restoration margin line of the digital restoration design. However, in some cases, the dentist may also choose to perform an additional step of polishing or grinding the restoration material so that the restoration margin line shifts from that defined in the digital restoration design.

Fig. 5 illustrates the creation of a digital restoration design for a superior restoration using the detected intersection.

The digital anatomies of the teeth 539 are arranged relative to the 3D digital representation 540 according to the preferred relative arrangement in which the surface of the digital anatomies of the teeth is positioned such that the upper restoration lifts the patient's bite. The digital anatomies of the teeth and the digital representation in 3D can be arranged with each other by expressing the digital anatomies of the teeth in the same coordinate system as the digital representation in 3D.

Digital tooth anatomies can be obtained from a library of tooth templates based on the dentist's preferences.

Intersection 542 is determined using a computer-implemented algorithm configured to detect surface-to-surface intersections applied to the 3D digital representation and digital anatomies of the teeth. The intersection can be expressed as a 3D spline that has the shape and position of the intersection relative to the digital anatomies of the teeth and / or the 3D digital representation of the teeth.

Restoration margin line 546 of the digital restoration design can be obtained by copying the determined intersection. Digital anatomies of teeth 539, 3D digital representation 540, and intersection 542 and / or restoration margin line 546 can be displayed to the operator in a displayed user interface, e.g. ex. on a computer screen.

The restoration margin line obtained by copying the intersection can be adjusted using suitable computer implemented algorithms, such as an algorithm configured to smooth the restoration margin line. If the operator prefers to adjust the restore margin line manually, he can do so using, eg. ex. a computer mouse to drag sections of the restore margin line according to your preferences. But this manual stage is completely voluntary and the digital restoration design can be created without the operator setting the restoration margin line himself.

Fig. 5B shows a schematic of the created digital restoration design 544. When the restoration margin line 546 has been defined, the outer surface 548 and the inner surface 549 of the digital restoration design 544 are obtained from the parts of digital anatomy of teeth 539 and 540 coronal digital representation to the restoration margin line 546.

Fig. 6 illustrates the use of Boolean subtraction from solid digital structures in creating a digital restoration design for superior restoration.

In Fig. 6A, the obtained digital tooth anatomies 639 and the 3D digital representation 640 are in the form of digital solid structures. The two solid digital structures are arranged in a common coordinate system according to their preferred relative arrangement in which their intersection 642 is as indicated in the Figure.

The common coordinate system can be, e.g. ex. one in which the digital representation in 3D is already expressed. The digital restoration design is created by boolean subtraction of the 3D digital representation from the digital anatomies of the teeth as described in relation to Fig. 1C.

In Fig. 6B, the 644 digital restoration design created by boolean subtraction is illustrated in conjunction with the 3D digital representation of the patient's unprepared teeth. The outer surface 648 of the design of the digital restoration 644 is shaped according to the shape of the digital anatomies of the teeth 639. The shape of the digital anatomies of the teeth and their preferred relative arrangement with respect to the 3D digital representation determines the shape of the occlusal table of the fabricated dental restoration. The inner surface 649 is shaped according to the shape of the 3D digital representation 640 so that the fabricated dental restoration can settle on the unprepared teeth. If undercut regions form in the digital restoration design, they can be virtually blocked to ensure that the restoration can settle on the unprepared teeth.

Fig. 7 illustrates how the digital restoration design can be adjusted to meet a minimum thickness criterion.

Fig. 7A shows a schematic of the 744 digital restoration design along with the 740 3D digital representation of the unprepared tooth for which it was created. The 744 digital restoration design has the outer surface 748 and the inner surface 749 created using, e.g. ex. the boolean subtraction described in connection with Fig. 6. In Fig. 7A, a frame 753 is indicated on the part of the restoration margin line 746 seen on the left side of the figure.

Fig. 7B-7D shows a close-up of the 753 frame and how the digital restoration design can be adjusted to meet a minimum thickness criteria.

In Fig. 7B it is seen that the thickness of the digital restoration design, ie the distance between the outer surface 748 and the inner surface 749 is very small at the restoration margin line 746. In fact, the restoration design digital tapers near the restoration margin line, which is very difficult to do with eg. ex. drilling technology and makes digital restoration design very fragile in this region.

The problem region 755 of the digital restoration design illustrated in Fig. 7C is identified by examining the digital restoration design against one or more minimum thickness criteria, eg. ex. that the thickness should not be less than a minimum value. The minimum thickness can be, eg. ex. 0.2 mm. The problem region can be identified, eg. ex. defining a displacement surface 756 from the 3D digital representation at a distance according to the minimum thickness criteria and determining which regions of the digital restoration design are located between the 3D digital representation 740 and the displacement surface 756.

Fig. 7D illustrates one way to adjust the digital restoration design in the problem region to provide that the minimum thickness criterion is met. In the problem region, the exterior surface of the digital restoration design is digitally removed and replaced with a new surface. The new surface is generated from a horizontal part 7571 on the restoration margin line, a vertical part 7572 parallel to the inner surface 749, and a twist 7573 connecting the two. The new surface is combined with part 758 of the exterior surface that already meets the minimum thickness criteria.

In a user interface configured to perform the steps of the described procedure, the user can be provided with options for, eg. ex. define the length of the horizontal part 7571, the length of the twist 7573 and the angle of the twist in relation to the horizontal part. Using these three parameters to fine-tune the digital restoration design, a connecting surface can be generated that connects the end of the kink to a point in the digital anatomy of the teeth to complete the outer surface of the digital restoration design. The connecting surface preferably provides a smooth transition from the kink to the outer surface of the digital anatomy of the teeth.

When the problem region is in the restoration margin line of the digital restoration design, the problem region can be digitally removed from the digital restoration design. This adjustment of the digital restoration design typically causes the restoration margin line to move upward, i.e. toward the occlusal table of the digital restoration design. For a restoration where the temporary dental restoration configured to be placed on the patient's unprepared teeth, this movement of the restoration margin line is not a problem since there is no tooth preparation line that must be aligned to ensure a suitable form of digital restorative design and dental restoration made from it. Also when the

When the dental restoration has been fabricated from this fitted digital restoration design, it has a finite thickness at the restoration margin line so that an edge is formed. This can cause irritation when the dental restoration is placed on the patient's teeth. However, the edge and thus irritation can be significantly reduced by polishing the fabricated restoration.

Fig. 8 illustrates how the digital restoration design can be adjusted to provide compensation for the bur.

It may be advantageous to apply a drill offset when the digital restoration design is for the fabrication of a dental restorative by drilling and the digital restoration design has sharp corners that cannot be accessed with a finite size drill. The digital restoration design adjusts to provide the bur offset. Figs 8A and 8B illustrate the problem. In Fig. 8A, the inner surface 849 of the digital restoration design 844 has a sharp corner. When the dental restoration is defined by drilling material, e.g. ex. From a zirconia blank, there is a region that cannot be accessed by the 860 bur due to its finite size. In the fabricated dental restoration 833 seen in Fig. 8B, there is therefore a region of remaining material 861 on the inner surface 835 of dental restoration 833 caused by the rounded tip of the bur 860. The region of remaining material 861 It will collide with tooth 827 and thus prevent the dental restoration from being properly positioned on tooth 827.

Fig. 8C illustrates the offset of the bur by introducing an indentation 862 into the inner surface 849 of the digital restoration design 844. Here the diameter of the dent 862 is chosen to be equal to the diameter of the bur 860 intended for use in the manufacture of dental restoration. However, you can also choose to be, e.g. ex. greater than the diameter of the cutter. In Fig. 8C, indentation 862 is shaped as a semicircle with an edge located in the corner of the inner surface 849 and is oriented so that the indentation can be drilled in the dental restoration made with the bur parallel to the longitudinal axis of the dental restoration. Other forms of indentation can also be used, such as a rectangular indentation. As seen in Fig. 8D, the corresponding indentation 862 on the inner surface of fabricated dental restoration 833 provides that there is no region of the remaining material on inner surface 835 so that dental restoration 833 can be properly positioned on the tooth 827.

Fig. 9 illustrates how the digital restoration design can be adjusted to provide compensation for the bur.

In Fig. 9A, a square indentation is defined in the digital restoration design such that the edge of the indentation 9621 is aligned with the corner of the inner surface 949 of the digital restoration design 944. The central axis 9641 of the indentation it is indicated as parallel to the longitudinal axis of the dental restoration, which in many cases is advantageous during the drilling procedure.

The bur offset adjustment of the 944 dental restoration design provides that the interior surface of the fabricated dental restoration does not have a region of material remaining to prevent the dental restoration. is arranged on the corresponding tooth (s). However, when indentation is defined, the thickness of the 944 digital restoration design and therefore of the fabricated dental restoration is reduced in the indentation which in some cases would make the fabricated dental restoration brittle.

An approach to solving this problem is illustrated in Fig. 9B. Here, the indentation 9622 is offset from the center of the dental restoration design compared to the indentation 9621 seen in Fig. 9A. The center axis 9642 of the indentation 9622 is thus offset relative to the center axis 9641 of 9621. This may be applicable, eg. ex. when the dental restoration has an occlusal surface with a depression in the center. The indentation 9622 then moves towards the thickest part of the dental restoration design 944. In this Figure, the central axis 9642 of the indentation 9622 is aligned with the corner of the inner surface 949 of the digital restoration design 944, but obviously others Offsets can also provide the same effect.

As illustrated in Fig. 9C, the displacement of the indentation 9622 as described in relation to Fig. 9B compared to the position of the indentation 9621 described in relation to Fig. 9A provides that the fabricated dental restoration is more thick in indentation as indicated by arrows 9631 and 9632.

Fig. 10 illustrates the curvature match at the restoration margin line of the dental restoration to provide a smooth transition of the teeth to a dental restoration at the restoration margin line. The 1044 digital restoration design is viewed in conjunction with the 1040 3D digital representation of the corresponding tooth. In Fig. 10A, a curvature adjustment area 1067 is indicated at the restoration margin line 1046. Within this area, a measure of the curvatures of the digital restoration design and 3D digital representation is determined in the restoration margin line (eg curvature can be expressed as its slope on the restoration margin line) and compared. If the curvatures (that is, the measurements of the curvatures) differ more than a predetermined value, the digital restoration design is tailored to have a curvature similar to the 3D digital representation on the restoration margin line. The adaptation of the curvature is smoothly performed, so that the portion adapted to the curvature 1069 of the outer surface 1048 of the digital restoration design 1044 gradually adapts to match the curvature of the 3D digital representation of the patient's teeth at restoration margin line 1046.

Outside of the limit 1068 of the curvature adjustment zone 1067, the digital restoration design 1044 is preferably unchanged, but maintains its shape. The curvature adjustment zone limit 1068 is identified either manually by marking a 3D spline in the 1044 digital restoration design or automatically by computer-implemented algorithms configured to define the transition zone limit, e.g. ex. based on a predefined distance from the restoration margin line or the point of contact between the digital restoration design and the neighboring tooth (natural or restorative).

The curvature match provides that the transition of the dental restoration into the tooth / teeth is smooth on a large scale and therefore the dental restoration feels and looks like a natural part of the tooth / teeth. Fig. 10B shows a close-up of the curvature adjustment area, in which the result of the curvature match is clearly seen. Initially, the exterior surface 1048 of the digital restoration design has an angle of approximately 45 degrees with respect to the 3D digital representation 1040. The coincident curvature portion 1069 of the exterior surface is substantially parallel to the 3D digital representation 1040 in the restoration margin line 1046. Between the restoration margin line 1046 and the curvature adjustment zone limit 1068, the adjusted surface smoothly changes from the curvature of the 1040 3D digital representation on the restoration margin line 1046 to the curvature of the digital restoration design at boundary 1068 such that an exterior surface of the digital restoration design without sharp edges is provided. The curvature fitted surface can be generated using computer implemented algorithms to generate a new surface from these curvature boundary conditions or by modifying the portion of the exterior surface of the digital restoration design in the area while obeying the conditions of curvature limit.

In addition to matching the curvature, a minimum thickness control as described above in relation to Fig. 7 can be applied to ensure that the coincident portion of the curvature of the digital restoration design is not too thin. This is illustrated in Fig. 10C. Where portion 1070 of the outer surface has a curvature that matches the digital restoration design on the restoration margin line and has an increased thickness to provide that the minimum thickness criterion is also met.

Fig. 11 shows the steps in a workflow to create a second digital restoration design for permanent restoration of the patient's teeth when they have been prepared.

When the first digital restoration design created for unprepared teeth is for the fabrication of a temporary dental restoration (eg, a set of upper teeth used to lift the patient's bite), the first digital restoration design can be used in creating a second digital restoration design for later permanent restoration.

When dental restoration is a temporary veneer of minimal preparation, it allows the patient to evaluate the appearance of their smile / teeth as determined by the veneer. When a dental restoration is a temporary set of upper teeth, it helps lift the patient's bite and accustom his muscles to the raised bite. Common to such temporary dental restorations fabricated from a first digital restoration design created using a procedure described herein is that removal of material from the tooth is not required to make room for the temporary restoration. In some cases, minimal tooth preparation is performed for e.g. ex. improve the adherence of the dental restoration made in the unprepared teeth. This may correspond, eg. ex. to remove less than a millimeter of the material from the teeth. With such minimal tooth preparation these can still be considered as unprepared teeth. Therefore, the substantive preparation of the teeth can be postponed, e.g. ex. after the patient has had a chance to assess the smile or the effect on bite augmentation. A second digital restoration design can then be created for fabrication of the permanent restoration based on a second 3D digital representation of the teeth obtained after the teeth have been prepared to accept the permanent restoration.

At step 1173, the first digital restoration design used to fabricate the temporary restoration is obtained. The first digital restoration design can be obtained using any of the embodiments described herein, an embodiment comprising the steps of obtaining a first 3D digital representation of the patient's unprepared teeth, obtaining a set of one or more digital anatomies of the teeth and create the first digital restoration design, e.g. ex. based on coronal portions of the first 3D digital representation and the digital anatomies of the teeth. The first digital restoration design can be created, e.g. ex. using a boolean subtraction as described above in relation to Fig. 6 or any other suitable technique to create the first digital restoration design.

At step 1174 a second 3D digital representation of the patient's prepared teeth is obtained. Before obtaining the second 3D digital representation, a dentist has prepared the teeth by removing material from the tooth to make room for permanent dental restoration.

Both the first and second digital 3D representations can be obtained by intraoral scanning using, eg. ex. a TRIOS intraoral scanner or any of the other techniques known to the person skilled in the art, such as scanning an impression of the patient's teeth or a physical model manufactured from said impression.

The workflow in Fig. 11 can be started when the first and second digital 3D representations are obtained. All dental work on the patient's teeth is complete when the workflow begins.

At step 1175, a tooth preparation line is identified on the second 3D digital representation. The tooth preparation line marks the part of a prepared tooth that will align with the restoration margin line of the permanent dental restoration when it is seated on the prepared tooth. The tooth preparation line can, e.g. ex. Automatically identify using computer-implemented algorithms configured to analyze the second 3D digital representation of the prepared teeth. Identification may be based on an analysis of geometry and / or texture of the second 3D digital representation, depending on the character of the second 3D digital representation.

At step 1176, the second digital restoration design is created based on the first digital restoration design and the second 3D digital representation. The creation involves executing computer-implemented algorithms configured to generate a connection surface connecting the tooth preparation line and the exterior surface of the first digital restoration design. The line where the connection surface connects to the first digital restoration design can be determined by the operator or automatically. The connection surface can be connected to or coronally connected to the first digital restoration design on your restoration margin line, which in many cases provides a smoother outer surface for the second digital restoration design. The inner surface of the second digital restoration design is created based on the portion of the second 3D digital representation corresponding to the prepared tooth, that is, the part on which the fabricated permanent restoration will sit. In this way, the permanent dental restoration can settle on prepared teeth and has an outer surface with e.g. ex. an occlusal table according to that of the temporary upper teeth. Preferably, the inner surface is offset from the surface of the second 3D digital representation to provide space for the cement used to bond the fabricated dental restoration to the prepared tooth.

In addition to, or instead of, using the first digital restoration design, digital anatomies of the teeth can be used when creating the second digital restoration design. The digital anatomies of the teeth are arranged in relation to the second 3D digital representation and the connecting surface connects the tooth preparation line and the outer surface of the digital anatomies of the teeth.

Fig. 12 shows a schematic of how the second digital restoration design can be created for the fabrication of a permanent dental restoration for the patient's prepared teeth. In this example, the dental restoration is a superior restoration, but the procedure is equally applicable to other dental restorations, such as veneer veneers.

In Fig. 12A, the digital restoration design for the 1244 temporary dental restoration (also called the first digital restoration design) and the second 1277 digital 3D representation of the prepared teeth are arranged with each other according to the arrangement of the first restoration design digital in relation to the patient's unprepared teeth.

If some of the neighboring teeth are not prepared so that their surfaces are identical in the first and second 3D digital representation, these surfaces can be used to arrange the second 3D digital representation relative to the first 3D digital representation. Based on knowledge of the relative arrangement of the first digital restoration design and the first 3D digital representation, the correct relative arrangement of the first digital restoration design and the second 3D digital representation can be deduced. The arrangement can also be based on soft tissue, such as the paddle structure in the upper jaw. An articulator can also be used to determine the correct relative arrangement of the first digital restoration design and the second 3D digital representation. The arrangement can take the form of determining transformation matrices to represent the different units in a common coordinate system, such as transformation matrices to represent the second 3D digital representation and the first digital restoration design in the coordinate system of the first 3D digital representation.

The tooth preparation line 1278 of the second digital 3D representation 1277 is identified, e.g. ex. by feature detection and / or by an operator indicating the position of the tooth preparation line on a display of the second provided 1277 3D digital representation, e.g. ex. on a computer screen.

The generated connection surface 1279 extends between the tooth preparation line 1278 and the exterior surface 1248 of the first digital restoration design 1244. The portion of the exterior surface 1248 above the point where the connection surface contacts the first digital restoration design forms the coronal part of the outer surface of the second digital restoration design, while the connecting surface 1279 forms a cervical part of the outer surface of the second digital restoration design.

Fig. 12B shows a schematic cross section of the dental restoration 1280 fabricated from the second digital restoration design of Fig. 12a. The inner surface 1235 is shaped to allow the permanent dental restoration to settle on the prepared tooth 1281 and the outer surface 1236 is such that the occlusal table 1230 with the restoration rises compared to the occlusal table 1228 of the teeth in its form (unprepared) 1229 before bite increase.

Fig. 13 shows a schematic of a system according to an embodiment of the invention. System 1382 comprises a computing device 1383 comprising a computer readable medium 1384 and a data processor in the form of a microprocessor 1385. The system further comprises a visual display unit 1388, a computer keyboard 1386 and a computer mouse 1387 for entering data and activating virtual buttons of a user interface displayed on the 1388 visual display unit. The 1388 visual display unit may be, eg. ex. a computer screen.

The 1383 computing device is capable of obtaining at least a 3D digital representation of a portion of the patient's teeth for which a dental restoration will be designed and fabricated, and at least one digital anatomy of the teeth that will be used to determine the shape of the outer surface of the dental restoration. The obtained 3D digital representation and digital anatomies of the teeth can be stored on the 1384 computer readable medium and provided to the 1385 processor. The 1382 system is configured to allow an operator to provide the 3D digital representation and digital anatomies of the teeth. teeth together to reflect the preferred arrangement of the outer surface of the fabricated dental restoration relative to the patient's teeth. For a superior restoration, the preferred arrangement is one that provides the desired increase in patient bite, i.e. where the dental restoration elevates the occlusal table of the teeth. This can be done by viewing the 3D digital representation and digital anatomies of the teeth on a user interface represented on the 1388 visual display unit and the operator can adjust their relative arrangement using, e.g. ex. the 1387 computer mouse or the 1386 computer keyboard. The 1383 computing device can be configured to execute algorithms to create the digital restoration design, eg. ex. based on coronal portions of the 3D digital representation and the digital anatomies of the teeth. Algorithms can be based, e.g. ex. in a Boolean subtraction of the solid digital structures as described above in relation to Figs. 1 and 6.

The 1383 computing device is also capable of receiving a 3D digital representation of the patient's teeth from a 1389 3D scanning device, such as the TRIOS intraoral scanner manufactured by 3shape TRIOS A / S, or capable of receiving scan data from said 3D scanning device and forming a 3D digital representation of the patient's teeth based on said scanning data. The received or formed 3D digital representation may be stored on the computer readable medium 1384 and provided to the microprocessor 1385.

When different stages of a procedure according to the invention are performed, such as by arranging the 3D digital representation of the teeth and the digital anatomies of the teeth with each other, one or more options may be presented to the operator, for example, which digital anatomies of the teeth to select or if you want to create the digital restoration design using a Boolean subtraction. The options can be presented in a user interface displayed on the 1388 display unit.

The system may have a 1390 unit for transmitting the created digital restoration design, eg. ex. to a 1391 computer-aided manufacturing (CAM) device for fabricating the dental restoration or other computer system, e.g. ex. located in a milling center where dental restorations are manufactured. The unit for transmission can be a wired or wireless connection.

3D scanning of the patient's teeth using the 1389 3D scanning device can be performed in a dentist's office, while the creation of the digital restoration design is done in a dental laboratory. In such cases, the digital 3D representation of the patient's teeth can be provided to the dental laboratory, e.g. ex. through an internet connection.

Fig. 14 shows a schematic of a user interface according to an embodiment of the invention.

Fig. 14 shows a first part 1493 of the user interface 1492 in which a part of the 3D digital representation 1440 and a digital anatomy of the tooth 1439 are illustrated. The relative arrangement of the 3D digital representation and the Digital tooth anatomy can be adjusted with a 1497 digital movement tool. The virtual movement tool can be configured to grip, eg. ex. the digital anatomy of tooth 1439 and move it in the user interface using e.g. ex. a computer mouse. Computer-implemented algorithms can translate the change in relative arrangement into a change at the intersection 1442 of the two digital surfaces 1439, 1440.

The second part 1494 of the user interface comprises a data entry section 1495 for entering data related to, e.g. ex. if the digital restoration design will be created by boolean subtraction and / or if a minimum thickness correction will be applied to the created digital restoration design. A virtual push button 1496 is configured to create the digital restoration design taking into account the data entered in the data entry section 1495.

The user interface can be displayed on a display unit, such as a computer screen that is part of a system configured to implement the method according to the present invention.

Fig. 15 shows part of a screenshot 1598 from a user interface displaying a digital restoration design created for a superior restoration. The upper restoration is configured to sit on top of the patient's existing teeth, where it provides that the occlusal table of the teeth is raised, i.e. the tooth / restoration set has an occlusal table that is raised compared to the occlusal table of teeth.

The 1544 digital restoration design of the upper restoration is displayed on top of the 1540 3D digital representation of the teeth in the patient's upper jaw for which it was designed. In this figure, the 1546 restoration margin line is highlighted on the central left anterior tooth to highlight its location.

Fig. 16 shows a smooth curve defined from an irregular intersection.

The intersection between the digital anatomy of the teeth 1639 for a superior restoration is arranged in relation to the 3D digital representation of the unprepared tooth of the patient 1640. The intersection 1642 is very irregular, so that it will be difficult to fabricate the dental restoration from of a digital restoration design with a defined restoration margin by directly copying the intersection.

Instead, a smooth curve 1699 is defined in the 3D digital representation. The curve can be defined by using a computer algorithm that calculates a curve with suppressed fluctuations or by a operator you use, eg ex. a computer mouse to draw the curve on a visualization of the 3D digital representation and digital anatomy of the teeth.

The characteristics of the procedure described above and in the following paragraphs can be implemented in software and carried out in a data processing system or other processing means originated by the execution of instructions executable by computer. The instructions may be program code media loaded into memory, such as RAM, from a storage medium, or from another computer over a computer network. Alternatively, the features described can be implemented by wired circuitry instead of software or in combination with software.

Reference numbers of the selected figures

In the Figures, the reference numbers are provided in the format according to XYY where "X" is an indicator of the Figure number showing which Figure the reference is used in and YY is the indicator of the item number according to the following list.

Patient's teeth 20

Tooth intersected by cross line 21

Cross section of tooth 25

Unprepared teeth 27

Occlusal table of unprepared teeth 28

Original tooth shape 29

Original occlusal table of teeth 30

Tooth / Restoration Set 32

Superior Restoration 33

Interior restoration surface 35

Restoration exterior surface 36

Digital anatomy of a tooth / Digital anatomy of teeth 39

3D digital rendering 40

Intersection 42

Digital Restoration Design 44

Restoration margin line 46

Exterior surface of digital restoration design 48

Interior surface of the digital restoration design 49

Frame 53

Problem region 55

New surface in the problem region 57

Horizontal part of the new surface 571

Vertical part of the new surface 572

Twist on a new surface 573

Part of the outer surface that meets the minimum thickness criteria 58

Strawberry 60

Remaining material that blocks restoration from inserting correctly 61

Indentation 62

A first indentation 621

A displaced indentation 622

Restoration thickness in indentation 63

Central axis of the first indentation 641

Central axis of displaced indentation 642

Curvature adjustment area 67

Limit for adjusted portion of curvature 68

Adjusted Bend Portion 69

Curvature and adjusted portion of minimum thickness 70

Workflow in creating digital restoration design for permanent restoration 72 Second digital 3D rendering 77

Tooth Preparation Line 78

Connection surface 79

Second digital restoration design 80

Prepared tooth 81

System 82

Computing device 83

Computer readable medium 84

Hardware Data Processor / Microprocessor 85

Computer keyboard 86

Computer Mouse 87

Visual display unit 88

3D Scanning Device 89

Transmission unit 90

Computer Aided Manufacturing Device (CAM) 91

User interface 92

First part of the user interface 93

Second part of the user interface 94

Data entry section 95

Virtual Push Button 96

Digital Movement Tool 97

Screenshot 98

Smooth curve 99

Claims (11)

1. A procedure for creating a digital restoration design (544, 644) by using a computer to fabricate a dental restoration (433) for one or more of a patient's teeth, where the dental restoration is a restoration upper (433) to lift the occlusal table (328) from the patient's teeth, in which the procedure comprises: - obtaining a 3D digital representation (40, 540) of the patient's unprepared teeth (220, 327, 427); - obtaining a set of one or more digital anatomies of the teeth (539, 639) that express the desired objective shape of the patient's teeth; - arranging the digital anatomies of the teeth (539, 639) expressing the desired objective shape of the patient's teeth and the 3D digital representation of the patient's unprepared teeth (220, 327, 427) according to a relative arrangement in the that digital tooth anatomies (539, 639) expressing the desired objective shape of the patient's teeth lift the patient's bite; Y - creating a digital restoration design (544, 644) comprising a restoration margin line (546, 746) where the restoration margin line is obtained, at least partially, from an intersection (542) of the representation 3D digital (40, 540) of the patient's unprepared teeth (220, 327, 427) and digital anatomies of the teeth (539, 639) expressing the desired target shape of the patient's teeth. The method according to claim 1, wherein an outer surface (436, 548, 648) of the digital restoration design (544, 644) is formed, at least partially, by copying the portion of the digital anatomies of the teeth (539, 639) located coronally to the restoration margin line obtained. The method according to claim 1 or 2, wherein the method comprises defining a curve (1699) in the 3D digital representation (40, 540) of the patient's unprepared teeth (220, 327, 427) by smoothing the intersection to suppress fluctuations at the intersection along the longitudinal axis of the teeth, and where the restoration margin is obtained, at least partially, from the defined curve. The method according to claim 3, wherein the portion of the digital anatomies of the teeth (539, 639) on the basis of which the outer surface of the digital restoration design (544, 644) is formed by the defined curve , such as projecting the curve onto the digital anatomies of the teeth (539, 639). The method according to any of claims 1 to 4, wherein the creation of the digital restoration design (544, 644) comprises a Boolean subtraction of the 3D digital representation (40, 540) of the digital anatomies of the teeth (539, 639). The method according to any of claims 1 to 5, wherein an interior surface (549) of the digital restoration design (544, 644) is created, at least partially, by copying the portion of the 3D digital representation (40 , 540) of the unprepared teeth (220, 327, 427) located coronally to the obtained restoration margin line (546). The method according to any of claims 1 to 6, wherein the method comprises examining the digital restoration design (744) against one or more minimum thickness criteria to identify any problem regions (755). The method according to the preceding claim, wherein the method comprises adjusting the digital restoration design (744) in the problem regions (755) to provide that the minimum thickness criteria are met in these regions, 9. The method according to the preceding claim, wherein the adjustment comprises: - increasing the thickness of the digital restoration design (744) in the problem region (755) so that the minimum thickness criteria are met, and / or - digitally remove the problem region (755) from the digital restoration design. The method according to any of the preceding claims, wherein the digital restoration design (544, 644) is for the fabrication of the dental restoration (833) by milling and the method comprises adjusting the digital restoration design to provide a Drill offset, in which drill offset is provided by inserting one or more indentations (862) into the inner surface (849) of the digital restoration design. The method according to any of the preceding claims, wherein the method comprises adjusting the curvature of the digital restoration design (544, 644) on the restoration margin line (546, 1046, 1546) to match the curvature 3D digital rendering of the patient's teeth.